This data set is the topographic elevation point data derived from multiple return
light detection and ranging (LiDAR) measurements for four counties in Georgia. These
counties are: Burke, Columbia, Lincoln, and Richmond. The Statement of Work (SOW)
was developed by the National Oceanic and Atmospheric Administration's (NOAA) Coastal
Services Center (referred to as the Center) in partnership with the Georgia Department
of Natural Resources (GADNR) Environmental Protection Division (EPD). LiDAR data is
a remotely sensed high resolution elevation data collected by an airborne platform.
The LiDAR sensor uses a combination of laser range finding, GPS positioning, and inertial
measurement technologies. The LiDAR systems collect data point clouds that are used
to produce highly detailed Digital Elevation Models (DEMs) of the earth's terrain,
man-made structures, and vegetation. The LiDAR data acquisition and processing for
Burke, Lincoln, and Richmond County was performed in the Winter of 2011. The LiDAR
data was provided to NOAA CSC, as part of the 4 GA Counties of Elevation Data task
order. The 4 GA Counties of Elevation Data task order AOI encompassed approximately
1,739 square miles. The area of interest acquired and processed for Burke, Lincoln,
and Richmond County is approximately 1,386 square miles. The task order required the
LiDAR data to be collected at a nominal pulse spacing (NPS) of 1.0 meter. The LiDAR
data was collected to meet Fundamental Vertical Accuracy (FVA) Root Mean Square Error
(RMSE) of 18.0 cm or better at a 95% confidence level, so that when combined with
breaklines, the data adequately supports the generation of two (2) foot FEMA compliant
contours. The final LiDAR data was delivered in 5,000' x 5,000' tiles using North
American Datum 1983, Georgia State Plane Coordinate System, East Zone, and expressed
in US Survey Feet. For data storage and Digital Coast provisioning purposes, the NOAA
CSC converted the data to geographic coordinates and ellipsoid heights in meters.
Special Note: Temporal changes of water levels will be observed in any data from Richmond
and Lincoln counties overlapping any previously delivered data from Columbia County.
The final products include full classified LAS, hydrologically flattened four (4)
foot pixel raster DEM's of the bare earth surface in ESRI Floating Point Grid Format
(ArcGRID DEMs), and hydrologically flattened breaklines. The data were collected on
the following dates: Burke and Richmond Counties: December 13, 14, 17, 2011 Columbia
County February 26, 2011 Lincoln County December 18, 2011 The data contains las points
with the following classifications: Class 0 No Classification Class 2 Ground Class
7 Low Point (Noise) Class 9 Water Class 10 Land below sea level Class 12 Overlap

DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National
Oceanic and Atmospheric Administration, U.S. Department of Commerce843-740-1200coastal.info@noaa.gov

Dataset Point of Contact

DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National
Oceanic and Atmospheric Administration, U.S. Department of Commerce843-740-1200coastal.info@noaa.gov

Documentation links not available.

Date(s)

publication: 2012-09-01

Data Presentation Form:

Digital image

Dataset Progress Status

Complete

Data Update Frequency:

As needed

Purpose:

The purpose of this data is for use in coastal management decision making, including
applications such as flood mapping, hydrologic modeling, risk map analysis, and water
rights management.

Use Limitations

These data depict the elevations at the time of the survey and are only accurate for
that time. Users should be aware that
temporal changes may have occurred since this data set was collected and some parts
of this data may no longer represent actual surface
conditions. Users should not use this data for critical applications without a full
awareness of its limitations. Any conclusions drawn
from analysis of this information are not the responsibility of NOAA or any of its
partners. These data are NOT to be used for navigational purposes.

While every effort has been made to ensure that these data are accurate and reliable
within the limits of the current
state of the art, NOAA cannot assume liability for any damages caused by any errors
or omissions in the data, nor as a result of the
failure of the data to function on a particular system. NOAA makes no warranty, expressed
or implied, nor does the fact of distribution
constitute such a warranty.

Originator(s)

DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National
Oceanic and Atmospheric Administration, U.S. Department of Commerce

Georgia Department of Natural Resources (GADNR)

Publisher(s)

DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National
Oceanic and Atmospheric Administration, U.S. Department of Commerce

Time Period:

2011-12-13 to 2012-02-26

Spatial Reference System:

urn:ogc:def:crs:EPSG::4269

Spatial Bounding Box Coordinates:

N: 33.982767

S: 32.797092

E: -81.540949

W: -82.641278

Spatial Coverage Map:

Theme keywords

None

Bathymetry/Topography

Model

DEM

Raster

Breaklines

Remote Sensing

Elevation

LiDAR

Place keywords

None

United States

Georgia

Burke County

Columbia County

Lincoln County

Richmond County

Use Constraints

No constraint information available

Fees

Fee information not available.

Lineage information for: dataset

Processor

Woolpert, Inc.

Woolpert, Inc.

Woolpert, Inc.

Woolpert, Inc.

Woolpert, Inc.

DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National
Oceanic and Atmospheric Administration, U.S. Department of Commerce

DOC/NOAA/NESDIS/NCEI > National Centers of Environmental Information, NESDIS, NOAA,
U.S. Department of Commerce

Processing Steps

2011-12-13T00:00:00 - Using a Leica LiDAR system, 100 flight lines of high density data, at a nominal pulse
spacing (NPS) of 1.0 meter, were collected over Burke, Lincoln and Richmond Counties,
GA (approximately 1,386 square miles). Multiple returns were recorded for each laser
pulse along with an intensity value for each return. A total of six (6) missions were
flown on December 13, 14, 17, and 18 in 2011. The geoid used to reduce satellite derived
elevations to orthometric heights was Geoid09. The horizontal datum used for this
survey is North American Datum 1983, Georgia State Plane Coordinate System, East Zone,
and expressed in US Survey Feet. The vertical datum used for this survey is North
American Vertical Datum 1988 (NAVD88), and expressed in US Survey Feet. Airborne GPS
data was differentially processed and integrated with the post processed IMU data
to derive a smoothed best estimate of trajectory (SBET). The SBET was used to reduce
the LiDAR slant range measurements to a raw reflective surface for each flight line.
System Parameters: Type of Scanner = Leica Data Acquisition Height = 6,500-feet AGL
Scanner Field of View = 40 degrees The Scan Frequency = 41.8 Hertz Pulse Repetition
Rate - 115.6 Kilohertz Aircraft Speed = 130 Knots Swath Width = 4,732-feet Number
of Returns Per Pulse = Maximum of 4 Distance Between Flight Lines = 3,289-feet

2011-12-13T00:00:00 - The Leica ALS50/60 LiDAR systems calibration and performance is verified on a periodic
basis using Woolpert's calibration range. The calibration range consists of a large
building and runway. The edges of the building and control points along the runway
have been located using conventional survey methods. Inertial measurement unit (IMU)
misalignment angles and horizontal accuracy are calculated by comparing the position
of the building edges between opposing flight lines. The scanner scale factor and
vertical accuracy is calculated through comparison of LiDAR data against control points
along the runway. Field calibration is performed on all flight lines to refine the
IMU misalignment angles. IMU misalignment angles are calculated from the relative
displacement of features within the overlap region of adjacent (and opposing) flight
lines. The raw LiDAR data is reduced using the refined misalignment angles.

2011-12-18T00:00:00 - Once the data acquisition and GPS processing phases are complete, the LiDAR data was
processed immediately to verify the coverage had no voids. The GPS and IMU data was
post processed using differential and Kalman filter algorithms to derive a best estimate
of trajectory. The quality of the solution was verified to be consistent with the
accuracy requirements of the task order.

2011-12-19T00:00:00 - The individual flight lines were inspected to ensure the systematic and residual errors
have been identified and removed. Then, the flight lines were compared to adjacent
flight lines for any mismatches to obtain a homogenous coverage throughout the project
area. The point cloud underwent a classification process to determine bare-earth points
and non-ground points utilizing "first and only" as well as "last of many" LiDAR returns.
This process determined bare-earth points (Class 2), noise (Class 7), water (Class
9) ignored ground (Class 10), unclassified data (Class 1), and overlap points (Class
12). The bare-earth (Class 2 - Ground) LiDAR points underwent a manual QA/QC step
to verify that artifacts have been removed from the bare-earth surface. The surveyed
ground control points are used to perform the accuracy checks and statistical analysis
of the LiDAR dataset.

2012-01-12T00:00:00 - Breaklines defining lakes, greater than two acres, and double-line streams, wider
than 100 feet (30.5 meters), were compiled using digital photogrammetric techniques
as part of the hydrographic flattening process and provided as a geodatabase containing
ESRI Polyline Z and Polygon Z feature classes. Breaklines defining water bodies and
streams were compiled for this task order. The breaklines were used to perform the
hydrologic flattening of water bodies, and gradient hydrologic flattening of double
line streams. Lakes, reservoirs and ponds, at a nominal minimum size of two (2) acres
or greater, were compiled as closed polygons. The closed water bodies were collected
at a constant elevation. Rivers and streams, at a nominal minimum width of 100 feet
(30.5 meters), were compiled in the direction of flow with both sides of the stream
maintaining an equal gradient elevation. The hydrologic flattening of the LiDAR data
was performed for inclusion in the National Elevation Dataset (NED). For this specific
project, NOAA requested that Woolpert define the Strom Thurmond Reservoir using a
contour set to match the water level used for the portion of the reservoir located
in Columbia County. This elevation is 323.55 survey feet. The Columbia county data
was acquired several months prior to the Burke, Richmond, and Lincoln Counties. Due
to this, the water levels in the reservoir were different. Woolpert set the contour
to 325.55 survey feet and classified the las and produced the required products using
the contour derived Strom Thurmond Reservoir.

2012-08-01T00:00:00 - The NOAA Coastal Services Center (CSC) received the files in las format. The files
contained lidar elevation and intensity measurements. The data were in State Plane
projection (NAD83, Georgia East), and vertically referenced to NAVD88 using the Geoid
09 model. Both horizontal and vertical units were in survey feet. CSC performed the
following processing for data storage and Digital Coast provisioning purposes: 1.
The data were converted from Georgia State Plane coordinates to geographic (NAD83)
coordinates. 2. The data were converted from orthometric (NAVD88) heights to ellipsoidal
heights (GRS80) using Geoid09. 3. The data were converted from vertical units of survey
feet to meters. 4. Elevation outliers were removed. 5. The data were converted to
LAZ format.

2013-01-22T00:00:00 - The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp
transfer from the NOAA Coastal Services Center. The data are currently
being served via NOAA CSC Digital Coast at http://www.csc.noaa.gov/digitalcoast/.
The data can be used to re-populate the system. The data are archived in LAS or LAZ
format.
The LAS format is an industry standard for LiDAR data developed by the American Society
of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless compressed version
of
LAS developed by Martin Isenburg (http://www.laszip.org/). The data are exclusively
in geographic coordinates (either NAD83 or ITRF94). The data are referenced vertically
to
the ellipsoid (either GRS80 or ITRF94), allowing for the ability to apply the most
up to date geoid model when transforming to orthometric heights.